canvas size even larger than 4096x4096?

[djsainthubert]

... would be cool to be able to do this, because I got more detail out of images by setting the canvas size larger than the resolution of the screen, but now that 4k monitors are around maybe there could be 8192x8192 option or something ridiculous?

Edit: it looks out of proportion kinda... so many like an exact size * 2, exact size * 4 option?